Switch point indicator for railway traffic controlling system control panels



Jan. 3, 1961 c, JACKSON 2,967,233

SWITCH POINT INDICATOR FOR RAILWAY TRAFFIC CONTROLLING S Filed March 21,1957 YSTEM CONTROL PANELS 2 Sheets-Sheet 1 I FIG.3.Y

INVENTOR. Y C.T.JACKSON HIS ATTORNVEY Jan. 3, 1961 c T. JACKSON2,967,233

SWITCH POINT INDICATOR FOR RAILWAY TRAFFIC CONTROLLING SYSTEM CONTROLPANELS Filed March 21, 1957 2 Sheets-Sheet 2 F|G.4. 28 i i INVENTOR.

C.T. JACKSON 'ZMW HIS ATTORNEY Unie States Patent SWITCH POINT INDICATORFOR RAILWAY TRAFFIC CONTROLLING SYSTEM CON- TROL PANELS Carlton T.Jackson, Conesus, N.Y., assignor to General Railway Signal Company,Rochester, N.Y.

Filed Mar. 21, 1957, Ser. No. 647,678

3 Claims. (Cl. 246-162) This invention relates to control and indicationpanels for railway centralized trafiic control systems, and moreparticularly relates to a track switch point indicator for use on suchpanels.

In the usual type of railway traffic control system, the remote switchesand signals are controlled by a control machine located at a centralpoint in the system. The control machine is provided with a controlpanel having a track layout suitably engraved thereon with the necessarycontrol buttons, signal lights and track switches appropriately locatedto simulate the actual track layout being controlled. Upon operation ofthe control buttons to set up a certain train route, the remote trackswitches are operated accordingly and indications are received back atthe control point which operate the electromagnetic switch pointindicators on the control panel to correspond to the position of theactual remotely located track switches.

Such a control panel must of necessity be miniature in size. Thisrequires an electro-magnetic switch point indicator of small compactsize which is reliable and endurable in operation.

The present invention proposes an electro-magnetic structure whichoperates a rotatable armature to either one of two extreme positions.This magnetic structure is fastened to the back of the panel. Theindicating arms of the switch point indicator are located on the frontof the panel where they are visable to the operator. They are positionedwithin and coact with the engraved or grooved track layout to form atrack route in accordance with their operated positions. Theseindicating arms are an integral part of a cylindrical bearing portion,the'arms extending radially therefrom. The cylindrical bearingportion ishollow and extends through an opening 'in the panel where it isconnected to the rotatably mounted armature. Thus, any movement of thearmature is transmitted to the indicating arms and is visual to theoperator who will know the exact position of the track switch. Theextent of armature travel is determined by the movement of theindication arms which come to a stop when they bear against the edges ofthe grooved track layout in their extreme operated positions.

The present invention also proposes an internally mounted indicator lampwhose light beam is visible in a specified color on the front of thepanel, located in the center of the indicating arms. This light beam istransmitted through a translucent rod and a color glass which arepositioned in the hollow cylindrical bearing portion of the indicatingarm assembly. This indicator lamp may be used for any suitable purpose,but primarily it is used to indicate that, when lighted, that particulartrack switch is in use as part of the track route already set up. Thus,the operator, when setting up another track route, can readily see whichpart of the track layout is already in use for other track routes.

In the electromagnetic structure of the present invention, the peripheryof the magnetically cooperating surfaces of the pole pieces and thearmature is circular in shape; and, they are positioned in relation toeach other so that the airgap between a pole piece and the cooperatingportion of the armature is at its maximum when that particular polepiece is deactivated. When a particular pole piece is activated, themagnetic pull between that pole piece and the cooperating portion of thearmature produces a rotational effort to cause the armature portion tomove towards coincidence with that pole piece, and as it does so therotative effort is reduced and thus the velocity of the armature isreduced. In addition, the cooperating portion of the armature tends tomove slightly beyond the position of minimum air gap which tends toproduce a reverse rotative effort to further reduce the velocity of thearmature as it rotates into its final stop position.

Other objects, advantages and characteristic features of the inventionwill be brought out as the description thereof progresses. Referencewill be made to the accompanying drawings wherein like parts arereferred to by like reference characters and in which:

Fig. 1 is a front elevational view of a portion of a typical controlpanel showing a partial track layout with switch point indicators of thepresent invention applied thereto;

Fig. 2 is a top view of the switch point indicator of the presentinvention with the top plate partially broken away to show other partsin full and cross section;

Fig. 3 is a front end view of the switch point indicator of the presentinvention with parts shown in section and taken substantially on theline 3--3 of Fig. 2;

Fig. 4 is a sectional side elevation of the switch point indicator ofthe present invention showing the magnetic structure and takensubstantially on the line 4-4 of Fig. 2;

Fig. 5 is a sectional side elevation of the switch point indicator ofthe present invention showing the mounting for the indication lamp, thearmature and the indicator arm assembly and taken substantially on theline 5-5 of Fig. 2;

Fig. 6 is a back end view of the switch point indicator of the presentinvention with parts broken away and parts in section to clarify theshowing;

Fig. 7 is a top view of the indication lamp and mounting means withparts being broken away and in section for clearness; and

Fig. 8 is another partial vieW of the control panel track layout showinga switch point indicator assembled for operation on a crossover which islocated in a direction opposite to the crossover shown in Fig. 1.

Referring now more particularly to Fig. 1, there has been shown asection of a typical control and indication panel P which is made fromblack insulation board. Grooves are cut in the panel P to simulate atrack layout which consists of two main tracks 11 and 12 and a siding 1Grooves are also cut in the panel to simulate a 13. crossover betweenthe tracks 11 and 12 and an entrance from the track 12 to the siding 13.The base of each of these grooves is painted white so that the tracklayout stands out against the black background.

A switch point indicator S1 constructed in accordance with the presentinvention and having two indicating arms is mounted on the panel P at acrossover point; Whereas, a. switch point indicator S2 having oneindication arm is mounted on the panel P at a siding entrance point.These indicator arms lie within the grooved sections of the panel P andare operable to either a closed switch position as shown in full linesor an open switch position .as shown in dotted lines.

Referring now more particularly to Figs. 2 to 6 inelusive, the switchpoint indicator assembly comprises a yoke 15 of suitable magneticmaterial, the top flat por tion of which terminates at one end into tworight-angleleg portions 16. A front plate 17 of suitable non-magneticmaterial such as aiuminum, is fastened to the other end of the yoke bymeans of screws 18 to form a framework of substantially inverted U-shape(see Fig. 4). Two cores 19 are respectively mounted on the two legs 16by means of screws 21. An energizing coil 23 is suitably mounted on eachof the cores l9 and is held in position by the split rings 24. Acircular pole piece 2%; of suitable magnetic material is adjustablymounted on each of the cores 19. Each pole piece 28 has a circular holeslightly off center which hole permits it to be eccentrically mountedover the end of its core 19, the end portion 38 of which is reduced incross section. A screw 22 is inserted through a hole in plate 17 andpasses through the off-center. hole of the pole piece 20 to cooperatewith threads in the associated core 19. The screw 22 can then betightened to firmly hold pole piece 2% between the shoulder on core 19and the plate 17.

The front plate It? is provided with an integral upturned angularbracket 25, thus forming a U-shaped structure with two spaced side walls(see Fig. 5). These two side walls are provided with bushings 26 locatedin openings disposed directly opposite each other. These bushings arepreferably made of nylon, Teflon or some other suitable material havinga low friction constant. The two spaced bushings 26 form bearingsurfaces for a hollow shaft 27 which extends through the two side wallsand carries an armature member 28.

The indicator arm structure comprises a hollow cylindrical main portion29 having arms 36 extending radially therefrom. The cylindrical portion29 is mounted within the hollow shaft 27 in a manner whereby it r0-tates with the armature 28. In assembly, the armature 28 is held inposition between the two side walls formed by the bracket 25 and thefront plate 17 and the hollow shaft 27 is slid into position, passingthrough the two bushings 26 and a hole in the armature 28. The mainassembly is now fastened to the panel P (indicated by dot and dashlines) by means of screws 31 which pass through the panel P from thefront side and thread into the front plate 17. The indicating armstructure 29-30 is now inserted through a hole in the panel P from thefront side into the hollow shaft 27. A set screw 32, threaded into thebottom section of the armature 28, passes through a hole in the hollowshaft 27 and clamps against the cylindrical portion 29 of the indicatingarm assembly. It can now be seen that the armature 28 and the indicatingarm assembly 29-30 are securely fastened together and are mounted forrotation on the hollow shaft 27.

Referring now more particularly to the magnetic structure of the switchpoint indicator, as shown in Fig. 3, the armature 28 has an upperarcuate surface for magnetic cooperation with an arcuate portion of theyoke plate 15, and also two lower arcuate surfaces 36 for magneticcooperation with the two pole pieces 20. The yoke plate 15 is providedwith an arcuate groove 37 therein which forms a path of travel for thearmature surface 35, a very small airgap appearing thercbetween. Thebody of the armature member 28 forming the arcuate surface 35 is soconstructed that the movement of the armature 28 does not materiallychange the magnetic reluctance of the path for flux through the smallairgap between surface 35 and yoke plate 15. The lower arcuate surfaces36 are located in a position to be attracted by their respective polepieces 20 when their respective coils 23 are energized. However, thebody of the armature member 28 is so shaped to form the two lowerarcuate surfaces 36 as to provide a flux path to either of the polepieces 20 to cause a high initial rotational torque; but formed so thatthe armature movement toward either position will cause some of themagnetic flux to be transferred to a path to the respective pole piece20 located beyond a line 33 drawn from the point of minimum airgap tothe center of the armature. This creates a reverse pull and slows thearmature movement as it comes to rest in its new position. Thus, theholding torque for either position is actually lower than the initialtorque on the armature. The relatively high initial torque is useful forovercoming its static friction and causing its initial movement towardits new position.

The pole pieces 20 are eccentrically mounted on the cores 19 so that theairgap between the pole pieces 20 and the arcuate surfaces 36 of thearmature 2% may be varied by turning the pole piece 29 on its core 19.As previously stated, these pole pieces 26 are mounted on a reduced endportion 33 of the cores 19 (see Fig. 4). The reduced end portion 33forms a shoulder and the pole piece 20 is clamped between this shoulderand the front plate 17 when the screw 22 is drawn tight. The adjustmentof the air gap is facilitated by loosening the screw 22 and turning thepole piece 2t) by means of an appropriate tool which is inserted intoone of the cross drilled holes 39 in the pole piece 2%.

When in operation, the switch point indicator is positioned in eitherone or the other of its extreme operated positions depending upon whichof the two coils 23 is energized. As viewed in Fig. 3, the left-handcoil 23 has been energized causing its pole piece 29 to attract thearmature 28 thereto, thus causing the armature to rotate in a clockwisedirection to its left-hand position as shown. The magnetic path formedby the flow of flux induced in the core 19 includes the core 19, polepiece 26, armature 23 and the yoke plate 15. This movement of thearmature 28 has caused a movement of the indicator arms 30 to a closedswitch position as shown in Fig. 1 and the track routes are lined up forthrough movements on both tracks 11 and 12. As previously mentioned,these indication arms 30 lie in a cut out groove portion of the panel Pand the extent of their movement is thus limited. This limited movementof the indication arms 30 provides stops for the armature 28. Thisstopping point is determined when the tip of the indication arms 30comes into contact with the edge of the grooves cut in the panel P, asshown at the points 40. Similarly, the energization of the right-handcoil 23 causes a reverse movement of the indication arms 30 to an openswitch position as shown in dotted lines. The armature movement will ofcourse stop when the tip of the indication arms comes into contact withthe other edge of the panel grooves as shown at the points 41.

When the operator sets up a track route for a crossover movement fromone track to another which calls for switch movements, the switch pointindicator S1 would react accordingly and the indicator arms 30 on thepanel P would move to an open switch position as shown by the. dottedlines in Fig. 1. This movement would occur because the indicationcircuit would cause the left-hand coil 23 to be deenergized and theright-hand coil 23 to be energized. With the right-hand coil 23energized, the flow of flux in its associated core 19 would causemovement of the armature 28 in a counterclockwise direction to itsright-hand position.

With reference again to the magnetic structure, particularly to theoperation of the armature as shown in Fig. 3 the location of the twopole pieces 20 and the armature 28 with respect to each other, alongwith their particular shapes, provides a structure having certainadvantages in operation. As can be seen, the periphery of the polepieces 20 is circular and the periphery of the two armature cooperatingsurfaces 36 is circular. With the armature 28 in its extreme clockwiseposition as shown, the airgap between the right-hand armature surface 36and right-hand pole piece 20 is at its maximum.

When the activating flux is built up in the magnetic structure, theright-hand pole piece 20 will attract the armature surface 36 thereto,causing the armature 28 to rotate in a counter-clockwise direction (seeFig. 3). Due to the strong magnetic pull required to initiate thearmature motion and due to the decreasing airgap, acceleration of thearmature movement would tend to be very rapid. But, since the rotationof the armature reduces the angle through which the magnetic pull isacting, the net rotative effort is reduced. As rotation of the armatureprogresses, the airgap between the armature surface 36 and the surfaceof the pole piece 20 soon reaches its minimum spacing. Furthermore, asthe leading edge of the armature surface 36 passes the center of the arc(indicated by the line 33) on the periphery of the pole piece 20, thearmature area on that side of center starts to increase, thus creating areverse magnetic pull which additionally tends to brake the armature.The net result is that when the armature 28 reaches its stop position,which in this case is determined when the indicating arms 30 reach theside of the groove in the panel P, the stopping impact is considerablyreduced.

The indication lamp L is mounted in a rectangular block of insulation 45which is mounted to the underside of the yoke plate by means of screws46 (see Figs. 5 and 6). This insulation block 45 is provided with atransverse hole 47 therethrough which is in alignment with the hollowcylindrical portion 29 of the indicator arm assembly. Resilient contactsprings are fitted one to each side of the insulation block 45 for thepurpose of holding the lamp L in position and completing the lampcircuit. These contact springs have an arched portion 48 lying withinthe transverse hole 47 and a finger portion 49 which extends to the rearto facilitate wiring connections.

The lamp L is of the conventional panel mounting type having a base 51of insulation and two metallic finger clips 52 which are connected tothe lamp filament and extend along the sides of the lamp envelope. Whenthe lamp L is inserted into the transverse hole 47 in the insulationblock 45, the two metallic finger clips 52 slide between the two archedportions 48 of the contact spring, thus compressing the spring portions48. This spring bias contacting means holds the lamp L in position andcompletes the circuit through the lamp filament.

The hollow cylindrical portion 29 of the indicating arm assemblyprovides a housing for a light transmitting rod 55 made from Lucite orsome other suitable type of light conducting material (see Fig. 5). Thislight transmitting rod 55 is slid into position from the front side ofthe panel P and is reduced in diameter at its panel end to accommodate acolor glass retainer 56. This retainer 56 is cylindrical in form and hasa ring 57, with a color glass insert 58 therein, mounted in its outsideend. The other end is provided with biased spring fingers 59. When theretainer 56 is pushed into place over the reduced portion of the lighttransmitting rod 55, the bias of the spring fingers 59 holds it inplace. Thus, the light beam from the lamp L is efficiently transmittedthrough the light transmitting rod 55 to the color glass insert 58 whereit is visible on the front of panel P.

A terminal board 65 of insulation material is mounted across the two legportions 16 of the top plate 15 to facilitate external wiringconnections. This terminal board 65 is held in place by the same twoscrews 21 which hold the cores 19., Suitable terminal posts 66 in thisterminal board 65 provide a connecting means between the wires from thecoils 23 and the external wiring. The contact fingers 49 from theindication lamp L extend through holes 67 to a point where externalwiring connection may be made.

The provision of an indication lamp whose indication is displayed whollywithin the switch point indicator device as shown and described hereinis considered very advantageous for use on control and indication panelsfor railway traffic controlling systems.

The switch point indicator of the present invention may be used on thepanel to indicate various switch locations such as are used oncrossovers and sidings in either direction, the only requirement beingthat different indicating arm assemblies are used to fit the trackcondition. For

example, in Fig. 1 there has been shown a switch point indicator S1having an indicating arm assembly wherein the indicating arms 39 arelocated in the upper right-hand corner and the lower left-hand corner tocorrespond to a track layout having a crossover from track 11 in alefthand direction to track 12.

In Fig. 8, there has been shown a track layout having a crossover fromtrack 11 in a right-hand direction to track 12 and the switch pointindicator S3 has its indicating arms 3i) located in the upper left-handcorner and the lower right-hand corner. Also in Fig. 1 there has beenshown a switch point indicator S2 located at the entrance to the sidingtrack 13 for trai'fic in a left-hand direction. As only one switch isrequired in the track layout, only one indication arm Si is necessary onthe panel layout, this being located in the upper right-hand corner. Ifthe entrance to the siding was in a right-hand direction, the indicatingarm 30 would be in the upper left-hand corner to correspond to the tracklayout. The switch point indicators are provided with multiple mountingholes so that the mounting screws 31 may always be located under theindicating arms 30 where they are not visible.

It should also be understood that the switch point indicator arms stayin their last operated positions if both their coils become deenergized.

Having thus shown and described one specific form which the presentinvention can assume and the manner in which it can be used, it shouldbe understood that various other adaptations, modifications, andalterations could be made in the structure, all without departing fromthe spirit or scope of the present invention, except as limited by theappending claims.

What I claim is:

1. A movable switch point indicator for a track dia gram on a panelcomprising, two laterally spaced U shaped electromagnetic structures,each of said structures having a pole piece at the same end of one legthereof, a yoke of magnetic material connecting the other legs of saidU-shaped magnetic structures, said yoke having an arcuate surface in aportion between the two magnetic structures, an armature pivotallydisposed adjoining said arcuate surface of said yoke and said polepieces having a plurality of arcuate surfaces in its periphery, one ofsaid surfaces being adjoining the arcuate portion of said yoke and otherof said arcuate surfaces of said armature being adjoining the polepieces of the two laterally disposed U-shaped electromagneticstructures, and a pointer indicative of a switch point in the trackdiagram secured to said armature so as to be rotated thereby, wherebyenergization of one of said electromagnetic structures rotates saidpointer in one direction by passage of flux through said armature fromsaid yoke to one of said pole pieces and the energization of the otherof said electromagnetic structures rotates said pointer in the otherdirection by the passage of fiuX through said armature from said yoke tothe other of said pole pieces.

2. A movable switch point indicator according to claim 1 wherein saidpole pieces are circular in shape and each of the pole pieces has apoint on its periphery which is adjoining an associated arcuate surfaceon said armature.

3. A movable switch point indicator according to claim 2. wherein eachof said pole pieces is eccentrically pivoted to permit adjustment byrotation of an air gap between a point on the periphery of that polepiece and an adjoining arcuate surface on said armature.

References Qited in the file of this patent UNITED STATES PATENTS1,165,904 Reed Dec. 28, 1915 2,149,225 Merkel Feb. 28, 1939 2,720,640Hewes Oct. 11, 1955

